Mk2 N/A - Supercharger Project

[Goldy]

The Car & Motivations

My car is a Red '91 UK MR2 with the 3S-FE engine in it. The engine the twin cam 16valve engine, also found in carinas rav4's and the avensis. It puts out around 120bhp as standard. I've always felt the performance of the car was slightly lacking. There is little or no tuning equipment avaliable for this engine off the shelf, so I fancied doing something a little different than a turbo conversion, hopefully a little cheaper, and mainly to see if it could be done. This project was concieved just under a year ago, and has been plodding on slowly since. Various issues have arisen over the course of the project that have been dealt with. Hopefully all the bugs in the design are ironed out now, and i've thought of most of the problems that need to be overcome to achieve this project.

Piccy Of the Car


Piccy Of my rather spacious engine bay



The Plan

The original plan was to fit an Eaton m45 supercharger (from a mini cooper S) above the manifold on the right hand side of the engine, running off the aircon pully.

Supercharger in proposed position


The original idea was to run it non intercooled with 5 psi of boost (max), for ease of simplicity, however this has since changed slightly, I will be using an intercooler mounted in the mk1 supercharger position to decrease charge tempratures, hopefully to decrease the chances of detonation and increase the power gains from fitting the supercharger.

Proposed position of intercooler


As the 3S-FE engine runs an air flow meter as standard, the ecu should be able to deal with the management of the engine with the supercharger (at low boost) without too many problems.

An SAFC-2 will be used to tweek the fueling and monitor the engine.

Work Done To Date

> Purchased the supercharger
> Test fitted the supercharger, measured / designed bracketry
> Test fitted the intercooler
> Purchased pipework, recirculating dump valve (to prevent the pipework blowing off when the throttle is closed!
> Purchased a tensioner pully
> Fitted SAFC-2 (wiring diagrams avaliable if required as 3S-FE has a different ecu plug layout to the rest of the mk2's)
> Decatted
> Fitted glove box gauge install - wideband air fuel ratio & boost gauge
> Fitted knock sensor
> Removed airbox & fitted cone filter to allow the afm to be relocated.

Work Still To Complete

All the parts required for the project are here now, I'm currently awaiting the fabrication of the inlets and outlets for the supercharger, and the bracketry.
Plans for the future include a custom exhaust manifold project. Eventually I want to swap the engine for a v6.

The work on the supercharger project is aiming to be completed by JAE this year [-o<

[Mark Edwards]

That is one hell of a mission you've undertaken there. What sort of results are you expecting to see when it's done?

[Goldy]

hoping for 160 bhp and a bagload more torque. I think 40bhp should deffo be achievable with this setup. Its pretty hard to put a figure on it though, so probably won't know for sure till its finished!

You can guestimate the power with the pressure ratio :

Original power x ( 14.7 + boost (psi) / 14.7)

[aliendoughnut]

Nice one I was thinking of doing the same to my 95 N/A how much do you think you have spent on this project

[Goldy]

I actually worked it out a month or two back. I've spent around £550 so far including the decat pipe. Though I think i've got most of the parts for the project now. I just need a few jubilee clips and connector hoses. The most expensive bits have been the wideband airfuel meter the supercharger and the Apexi SAFC 2

I'm getting the brackets and pipework made up by a mate so thats saving a bit of money

[EarL]

Goldy,
Are you going to make any modifications to the head to lower the compression, or run it with a thicker HG?

[Goldy]

My current compression ratio is 9.8:1 (turbo is 8.8:1 as far as I know).

I wont be lowering it as there really isnt any need. I'll only be running 5psi of boost max to start with which will be fine with adequate intercooling and running the car on optimax.

I may consider later lowering the compression for higher boost, but then things are going to get expensive, as i'll have run out of fueling.

Keep your eyes peeled on this, as i'm hopefully going to be fitting / setting this up in 3 weeks time

[EarL]

Ahh! I guess if youre going to be happy with 5psi, then it makes sense.

[Goldy]

Ahh! I guess if youre going to be happy with 5psi, then it makes sense.

I'd be nice to make more power, but realistically there isn't a lot of point in throwing lots of money at a 3S-FE engine. I think this is probably as far as the limits of tuning a 3S-FE will take me without spending mega bucks. The original idea was to get the power up a fair bit, without shelling out on an engine conversion. The long term plan is to eventually put in a V6 engine. Hopefully next year (funds permitting).

[Goldy]

Progress update:

Kris welded an inlet for me and we bolted it onto the charger... Tadaaaa


Began work on the brackets, started off by sticking a 90 degree bend in some stainless bar so the bracked would bolt on 2 sides of the engine


Next the clever bit, cut a plate to mount the end of the charger, a hole was cut through it to allow the pipe to pass though!


Next the mount for the nose of the charger was cut, drilled and tacked in place.


The mount was taken off and fully welded together.


We had a major problem with the tensioner, the aircon tensioner tensions in the up/down direction, the supercharger needs a back / forth tensioner else it won't do anything! We tried several different ways, but decided that it would be best to cut one of the arms off the aircon tensioner, and mount it so it would tilt on the block. A bar was weded up with a thread on the end so that the tensioner could be tensioned back and forth. Sorry I don't have any pics of this, it was probably one of the trickier bits.

Next a support bar was fabricated to bolt onto the opposite side of the charger and down to the block to really make it solid!


The pipework was extended, the whole lot was bolted up and the flexi uber pipe, off a landrover (cough cough) was attached to feed into the throttle body!

Tadaaaa

We measured the belt length though theres a bit of an issue with the inlet side, we're not quite sure how to make an attachment for it to connect to the airflow meter as its a really stupid shape! More brainstorming required, though I think we may have a solution

[Goldy]

We picked up a belt in the morning, had to get a 6 groove belt and chop it down to 4 grooves as it was the only one they had. We fitted the belt and imediately found a problem, the belt was rubbing against the engine mount. Not good. We needed to move the belt over. We decided to fabricate a new tensioner.... so.... out with the old :


Using a citroen van tensioner (won off ebay for £1.70) it finally came in handy. We drilled up a mounting plate to allow it to be tensioned. Needed to cut some of the rear of the tensioner down a little.


The tensioner was welded onto the mounting bracket... tadaaaa


Next to solve the inlet pipe problem....
Take one piece of rubber


Weld up a T tube for the dump valve


Take two jubilee clips, and some bonded rubber sheet .... and :


Sorted!!!


We plumbed it all in.... then... turned the key!!!!

uh oh disaster, it wouldn't idle properly, it wouldn't rev nicely, it died whenever you revved it! We found that the dump valve was putting so much air back round that it was forcing the airflow door to shut / flap about, basically cutting the fuel.

We decided to try to put the airflow meter on the other side of the charger.


Had to change a fair bit of the pipework around


Sooo nearly there...

Plumbed everything in dump valve, neatened everything up.


Time to turn the key,

it wasn't idling properly, so we had to increase the idle speed to 1000rpm to keep it running nicely. Went for a little test run in it.... Not good, no smooth boost, and then blew 3 of the pipes off. Not good at all.

Back to the workshop, turns out that the dump valve is connected the wrong way round. Quick bit of work and we've switched it around. Now idles properly, runs nicely.

Take it out for test drive number two. Seems to be running good. Give it a little bit of stick, the thing bloody flies!!!! Saw around 6 psi of boost at around 5k rpm. Decided to back off the throttle and go back to the workshop. As i pull in i realise there is smoke pouring from the back of the car..........

To be continued....

[MartG]

As i pull in i realise there is smoke pouring from the back of the car..........

Hope its nothing too serious/expensive =D>

[Goldy]

Thought I'd leave it on a bit of a cliffhanger...

Turns out that the dipstick wasn't in properly. Anyway that was enough to scare me!!! Drove it home like a granny. Its wasnt running properly still. It stutters if you run it a constant throttle for a long period of time. We're not sure the dump valve has a problem! The damn thing is pinking occasionally in mid revs under load.

We made it home. Removed the belt and plugged it back into n/a mode! I've driven back to manchester with it, and it seems to be running fine.

I'm going fully intercooled, and the relocation of the throttle and the air flow meter to the inlet side of the charger before running this again. I'll probably be retarding the timing slightly to around 8 degrees as well. Its been an adventure, but i'm really scared i've damaged my engine now.

Not sure whether to cut my losses and bin off this project now, i'm feelin a bit down about the results. I'm checking the state of the engine at the weekend. Fingers crossed eh

[MartG]

Probably worth getting it properly mapped, as its unlikely to run cleanly using existing maps which weren't designed for its current mechanical configuration.

[EarL]

Be a shame to give in now mate. Like MartG said, get it mapped and set up properly and you'll hava a reall different motor there. Seeing as you've had it running and driven and experienced what it's like, don't give up! I dougbt very much you done any harm, the 3SFE is tough as old boots.

You know it makes sense... =D>

[paul port]

Question...

Do you actually need a Dump Valve???

Other OEM Supercharger systems I've seen have the throttle mounted before the supercharger it's self. The supercharger is really just a fixed volume air pump, if the throttle is before and closed, then it just means the air entering the SC is at a low pressure, therefore the output of the SC is at low pressure...

These systems typically have a bypass valve - a flap that is opened under high plenum vacuum that bypasses SC input to output. This reduces the load the SC places on the engine and is typically open when cruzing on the road, only closing when you accelerate. Look at the other OEM Eaton SCs typically on Ebay, and you see it's built in.

This arrangement should resolve all your AFM issues.. as you never 'loose' metered air..

Paul.

[Goldy]

Cheers guys. I'm going to be checking it out at the weekend, theres a lot of noise from the top end at around 4k revs. I'm going to have a look & check the valve clearances.

Question...

Do you actually need a Dump Valve???

Other OEM Supercharger systems I've seen have the throttle mounted before the supercharger it's self. The supercharger is really just a fixed volume air pump, if the throttle is before and closed, then it just means the air entering the SC is at a low pressure, therefore the output of the SC is at low pressure...

These systems typically have a bypass valve - a flap that is opened under high plenum vacuum that bypasses SC input to output. This reduces the load the SC places on the engine and is typically open when cruzing on the road, only closing when you accelerate. Look at the other OEM Eaton SCs typically on Ebay, and you see it's built in.

This arrangement should resolve all your AFM issues.. as you never 'loose' metered air..

Paul.

Hey paul,

I need the dump valve at the moment as my throttle is on the pressure side of the charger. I proved why it was needed as I blew off 3 of the pipes without it present. I'll hopefully be relocating the throttle as you've described. I'd hope that'd sort the running issues!. I'm currently brainstorming on a boost controller / bypass system.

[paul port]

Yes... the suggestion was - move the throttle to before the Supercharger, and then you won't need the BOV!

You can probably survive without the bypass for now and just put up with the extra MPG hit when cruzing (as the Supercharger is still doing work)

Alternatively, I wonder if you could botch up a bypass using a boggo-cheap Recirculating dump valve (EG Demontweeks Sytec) as it's basically open under manifold vaccum??

Paul

[aaronjb]

Turns out that the dipstick wasn't in properly.

Wasn't in properly, or got blown out?

If it's getting blown out then that would imply that you're pressurising the crankcase - either shot rings (unlikely as it was fine before), or pressure entering via the PCV system..

Not sure what the PCV setup on the 3S-FE is like, but if it's anything like the standard setup on the 1ZZ-FE it's just not designed for seeing positive pressure in the intake system, which means you end up pumping boost pressure into the rocker cover and around the engine..

Worth looking into, certainly.

Other than that - top job that man

[Goldy]

Ah ha... Good point aaron, I hadn't thought of that. It could have been caused by that as the oil feed from the pcv returns to the throttle body, so your theory may be right. We just assumed we'd left it out as we'd been playing with it earlier. Relocating the throttle body would sort this as well i'd expect!. What do they do to solve the problem on the 1ZZ-FE?

Paul I was planning on using the dump valve as a bypass as it stays open under vaccum. I'm going to hook up a little setup that will open it to limit the boost as well.